Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Homogenates of guinea-pig left ventricle were fractionated by differential pelleting and by centrifugation on continuous sucrose density gradients. 2. The principal subcellular organelles of myocardium, characterized by their marker enzyme content, were resolved by density gradient centrifugation in a small-volume zonal rotor. The equilibrium densities (p) of the principal organelles are (with marker enzymes in parentheses): sarcolemma, 1-12 (5'-nucleotidase); lysosomes, 1-16 (N-acetyl-beta-glucosaminidase); mitochondria, 1-17 (cytochrome oxidase); peroxisomes, 1-18 (catalase); cytosol (lactate dehydrogenase). 3. The subcellular distribution of various adenosine triphosphatase activities and previously unassigned enzymes was determined. Leucyl-beta-naphthylamidase and gamma-glutamyl transpeptidase showed both cytosol and sarcolemma components. Ca2+-dependent adenosine triphosphatase showed dual localization to the mitochondria and to the sarcolemma.
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PMID:Analytical subcellular fractionation of guinea-pig myocardium. 14 54

Subcutaneous injection of iron dextran resulted in a hepatic siderosis within 2 weeks in rats, as previously reported for mice. Hepatic carcinomas as well as neoplastic nodules in rats were entirely or mainly free of stainable iron and, thus, could be readily identified histologically. In addition, early carcinogen-induced altered foci were resistant to iron accumulation. In rats fed 0.02% N-2-fluorenylacetamide (FAA) for 13 weeks, the number of iron-resistant foci identified following iron injection was the same as that observed with dietary iron overload. Histochemical investigation of enzymatic markers that have been used to identify foci in rats revealed that foci characterized by enzymatic reactions of positive gamma-glutamyl transpeptidase and decreased adenosine triphosphatase and glucose-6-phosphatase corresponded to those characterized by resistance to iron accumulation. However, in quantitative analysis of the early carcinogen-induced foci in rats given iron dextran following a diet containing 0.02% 2-FAA for 13 weeks, more lesions were detected by resistance to iron accumulation than by any of these other properties. There was considerable phenotypic heterogeneity among foci for the enzyme markers. It is concluded that resistance to iron accumulation is a more sensitive and reliable marker for early carcinogen-induced altered hepatocellular foci than is any other histochemical property.
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PMID:The sensitivity and heterogeneity of histochemical markers for altered foci involved in liver carcinogenesis. 22 50

Na-coupled D-glucose transport in rabbits with cis-diamminedichloride platinum (CDDP; cisplatin) induced acute renal failure (ARF) has been studied. ARF occurred at 3 days after injection of CDDP (3 mg/kg i.v.). Na-coupled D-glucose transport into brush-border membrane vesicles (BBMV) from both outer cortex (OC) and outer medulla (OM) of ARF rabbits under zero-trans condition was decreased. Increased Km (i.e., decreased affinity of transport carrier for D-glucose) in OC and decreased Vmax (i.e., decreased number of glucose carrier) in OM were observed in CDDP-induced ARF rabbits. Decrease glucose transport was also observed under equilibrium exchange condition. Intravesicular volume of BBMV from OC and OM of ARF rabbits was decreased. In homogenate and BBMV from OC and OM of ARF rabbits, activities of gamma-glutamyl transpeptidase and alkaline phosphatase (marker enzymes of brush-border membrane) were decreased. Activities of succinate dehydrogenase, glucose-6-phosphatase, and Na-K ATPase (marker enzymes of mitochondria, endoplasmic reticulum, and basal lateral membrane, respectively) were not affected by CDDP administration. These results suggested that one of the main target sites of CDDP in kidney is brush-border membrane (BBM) along the proximal tubule, that is, not only Na-coupled D-glucose transport carrier protein but also other proteins in BBM.
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PMID:Decreased sodium dependent D-glucose transport across renal brush-border membranes in cis-diamminedichloride platinum induced acute renal failure. 156 86

The common hookworm (Ancylostoma ceylanicum) infection of humans was studied in golden hamsters model system. Significant biochemical modulations were observed in hamster jejunal brush border membrane (BBM), the primary site of infection. Analysis of BBM at the peak of infection (3-weeks) revealed a marked decrease in the activities of sucrase, lactase and maltase, while activities of alkaline phosphatase, (Ca2+ + Mg2+)-ATPase and gamma-glutamyl transpeptidase were increased. Kinetic studies conducted with maltase, a superficially localised enzyme of jejunal BBM, revealed loss of enzyme active site during the infection. Among other constituents, the levels of cholesterol and triglycerides were significantly decreased with slight increase in phospholipid content in the infected animals. The hookworm infection also caused a decline in total hexose content indicating an altered membrane glycocalyx. Conversely, there was significant enhancement of hydroxyproline and sialic acid contents. SDS-PAGE analysis showed an enhancement in both low and high molecular weight proteins in jejunal BBM preparations of the infected group. Gel electrophoresis of glycoproteins further revealed the appearance of two additional peaks in the low molecular weight region and concomitant disappearance of a peak in the high molecular weight region. These results strongly support the view that the hookworm infection causes severe damage not to the site of attachment alone but also to the entire cell lining of the jejunum and therefore could influence overall digestion and absorption.
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PMID:Biochemical analysis of jejunal brush border membrane of golden hamster: pathogenic modulations due to ancylostomiasis. 159 19

Primary cultures of renal rabbit proximal tubule cells were initiated from a pure suspension of proximal tubule fragments. Proximal tubule cells were grown in a hormone-supplemented, serum-free medium containing low concentrations of antibiotics. Confluent monolayers exhibited multicellular dome formation, indicating the presence of transepithelial solute and water transport. Ultrastructural examination revealed a monolayer of polarized epithelial cells with tight junctions and sparse membraneous microvilli facing the culture medium. Time course biochemical characterization was performed using a palette of 12 enzymes, representative of important metabolic functions or pathways. Brush-border-associated enzymes (gamma-glutamyl transpeptidase and alanine aminopeptidase) were moderately reduced throughout the culture whereas alkaline phosphatase was markedly decreased at confluency. Mitochondrial and lysosomal marker enzymes were well preserved over the culture period. Glutathione-S-transferase activity remained stable during the 16-day culture period investigated. Glycolysis enzyme activities (lactate dehydrogenase and hexokinase) were enhanced, as a function of culture age. Na(+)-K(+)-ATPase activity rise was concomitant with the increase of glycolysis marker enzymes. In contrast, the gluconeogenesis marker enzyme, glucose-6-phosphatase, fell dramatically to reach a low level equivalent to 4% of the activity measured in isolated proximal tubules. Primary cultures exhibited several differentiated functions of the proximal tubule cell: (a) PTH alone was able to induce a significant stimulation of adenylate cyclase activity, unlike isoproterenol, thyrocalcitonin, and arginine vasopressin, and (b) sodium-dependent alpha-methylglucoside (AMG) transport was detected. This AMG uptake was selectively inhibited by phlorizin (5 X 10(-3) M), which is a competitive inhibitor of glucose uptake at the apical membrane. Complete characterization made it possible to investigate hitherto unexplored aspects of in vitro cultured proximal tubule cells. This primary culture model could provide a useful and reliable tool to investigate in vitro renal proximal tubule function, under normal conditions or after a drug-induced toxicity.
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PMID:Biochemical, functional, and morphological characterization of a primary culture of rabbit proximal tubule cells. 167

The purpose of this study was to determine if increasing dietary fat, either as saturated fat or polyunsaturated fat, would alter initiation of hepatocarcinogenesis by diethylnitrosamine (DEN) or 2-acetylaminofluorene (AAF). Rats were fed one of three purified diets: a low-fat (LF) diet (containing 5% of calories as safflower oil), a high saturated fat (HSF) diet (containing 48% of calories as palm oil) and a high polyunsaturated fat (HPUF) diet (containing 48% of calories as safflower oil). Four weeks later, all rats were subjected to partial hepatectomy (PH). Rats were then divided into four groups and received no carcinogen, DEN (10 mg/kg, p.o., 24 h after PH) or AAF (25 or 100 mg/kg, p.o., 12 h after PH). Five days later, all rats were fed an unrefined diet, and 9 weeks later, all rats were fed phenobarbital in the diet for 26 weeks as a tumor promoter. In rats initiated with DEN, the number of gamma-glutamyl transpeptidase-positive and ATPase-negative foci was higher in the rats fed the HPUF diet, but not the HSF diet, as compared to rats fed the LF diet. The incidence of neoplastic nodules, the mean focal volume and the volume fraction, however, were not significantly altered by dietary fat in DEN-injected rats. The dietary fat content of the diet did not affect the induction of altered hepatic foci or neoplastic nodules in rats initiated with AAF or receiving no initiation. This study shows that initiation of hepatocarcinogenesis can be influenced by dietary fat, but that the effect may be carcinogen-specific.
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PMID:Effect of dietary fat on the initiation of hepatocarcinogenesis by diethylnitrosamine or 2-acetylaminofluorene in rats. 167 61

The blood-brain barrier (BBB) in mammals is created and maintained by cerebral endothelial cells (cEC) that express specialized functional properties, including intercellular tight junctions, absence of fenestrae and specific membrane transport systems. It has been proposed that the differentiation of these characteristics, acquired during brain development, is controlled by the neural environment. Co-culture experiments of cloned cEC with astroglial cells, C6 glioma cells and cortical neurons, with plasma membranes or conditioned media of these cells, were used to study induction of some BBB characteristics in vitro. Activities of Na+,K(+)-ATPase and gamma-glutamyl transpeptidase (GGTP), an enzyme responsible for amino acid transport across the BBB, were taken as parameters for BBB function. Co-culture of cEC with C6 glioma cells caused a two-fold increase in GGTP activity and this activity was likewise amplified by incubation with plasma membrane fractions derived from C6 glioma cells, embryonic brain cells and cortical neurons; conditioned media (soluble factors) had no effect. Na+,K(+)-ATPase activity, estimated from the ouabain inhibitable fraction of 86Rb uptake, was increased by about 90% in cEC incubated with C6 glioma plasma membranes. We propose from these data that both neurons and glial cells confer BBB characteristics on cEC via cell-cell contact.
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PMID:Glial cells and neurons induce blood-brain barrier related enzymes in cultured cerebral endothelial cells. 167 6

In the present study the promoting activity of various PCB and PBB isomers and congeners in rat liver has been studied and compared with a variety of primary xenobiotic-mediated enzymatic changes in this target organ. Female Wistar rats were given diethylnitrosamine (DEN; 10 mg/kg body wt for 10 days) and were subsequently treated once weekly with polychlorinated biphenyls (150 or 15 mumol/kg body wt) for a total of 8 weeks. Additional groups of rats were administered 3,3',4,4'-tetrabromobiphenyl or 3-methylcholanthrene (8 weekly injections of 15 or 150 mumol/kg body wt, respectively) or were given phenobarbital (0.05% in the diet) until the end of the experiment. Reference groups were treated with the various test compounds without prior initiation. One week and 9 weeks after cessation of promoter treatment rats were killed and the volumetric fraction of enzyme-altered foci characterized by changes in adenosine triphosphatase and gamma-glutamyl transpeptidase activity was determined as a means to quantitatively assess the extent of preneoplastic response in this organ. Out of the series of polyhalogenated biphenyls tested, promoting effects were seen with the following compounds: 2,2',4,5'-tetrachlorobiphenyl, 3,3',4,4'-tetrachlorobiphenyl, 2,3,4,4',5-pentachlorobiphenyl, and 3,3',4,4'-tetrabromobiphenyl, whereas no significant effects were obtained with 4-monochlorobiphenyl. In rats not treated with DEN, the two strongly promoting agents 2,3,4,4',5-pentachlorobiphenyl and 3,3',4,4'-tetrachlorobiphenyl also significantly increased the volume fraction of enzyme-altered foci over the respective controls when analyzed at the second time point of investigation. In parallel experiments, induction of liver growth and of microsomal cytochrome P450 content in liver was found to correlate well with the promoting activity of the various xenobiotics, suggesting that these parameters may be used to predict the promoting activity of polyhalogenated biphenyls in a short term assay.
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PMID:Effects of polychlorinated biphenyls in rat liver: correlation between primary subcellular effects and promoting activity. 168 70

Several pharmaceutical agents, manufacturing chemicals, and environmental contaminants were found to act primarily as promoting agents in an initiation-promotion paradigm. The phenotypic distribution of four enzyme markers--placental glutathione-S-transferase (PGST), gamma-glutamyl transpeptidase (GGT), canalicular ATPase (ATPase), and glucose-6-phosphatase (G6Pase)--was analyzed in altered hepatic foci (AHF) by quantitative stereology. The number and volume distribution of AHF were determined for each promoter tested. For phenobarbital and 2,3,7,8-tetrachloro-p-dioxin, PGST and GGT together scored 100% of the AHF; for 1-(phenylazo)-2-naphthol (CI solvent yellow 14) and chlorendic acid, PGST alone marked 90% of the AHF; after chronic administration of WY-14,643, ATP and G6Pase were the predominant markers. In rats fed tamoxifen, G6P scored more than half of the AHF. Differences in the number of AHF promoted by each of these agents and in their phenotypic distributions may reflect the differentially responsive nature of individual initiated hepatocytes to the action of specific promoters. Since the chronic bioassay of suspected carcinogens does not allow one to differentiate between weak complete carcinogens and those carcinogenic agents that act in a reversible manner to promote the growth of previously initiated cells, the partial hepatectomy, altered-hepatic-focus model of cancer development is proposed as a supplement to the chronic bioassay for the identification of those carcinogenic agents that are primarily, if not exclusively, promoting agents in rat liver.
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PMID:An initiation-promotion assay in rat liver as a potential complement to the 2-year carcinogenesis bioassay. 185 24

Glutathione (GSH) and GSH-related enzymes, glutathione reductase (GR), gamma-glutamyl cysteine synthetase (gamma-GCS), gamma-glutamyl transpeptidase (gamma-GTP), glutathione S-transferase (GST) and adenosine triphosphatase (ATPase) enzymes were analysed to study the effect of busulfan on the defence mechanisms of the lens. All these enzymes were found to increase significantly except GSH which showed only 7.9% increase as compared to controls in precataractous stage. These results affirm that busulfan is capable of evoking a response from the enzymes involved in the various pathways of GSH enabling the lens to prolong its clarity. The cataractous lenses showed significant decrease in all these parameters. Here, the impairment of the defense mechanism (GST, GR) and the total ATPase may be attributed to the cumulative action of the drug which can react with -SH groups of these enzymes, ultimately causing opacification.
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PMID:Glutathione and glutathione-related enzymes in busulfan treated rat lens. 191 43


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